The invention relates generally to separable loadbreak connector systems for electric power systems, and more particularly to insulated loadbreak connector systems to interface deadfront electrical apparatus and power distribution cables.
Electrical power is typically transmitted from substations through cables which interconnect other cables and electrical apparatus in a power distribution network. The cables are typically terminated on bushings that may pass through walls of metal encased equipment such as capacitors, transformers or switchgear.
Because of increased safety, increased reliability and increased operability of the deadfront system, deadfront electrical apparatus is increasingly being used in lieu of livefront apparatus Using a deadfront system, because there is no exposed voltage, safety is increased for both the operator and the public, and the ability to operate the apparatus easily and efficiently either with grounded, visible break connection points or loadbreak connection points with a one or two man crew lessens the operating danger. The deadfront system has proven to be extremely reliable with very low failure rate.
Various safety codes and operating procedures for underground power systems require a visible break disconnect for safely performing routine maintenance work on the cable system, such as line energization checks, grounding, fault location, or hi-potting, may also be required. High voltage, separable connector systems have been developed that allow disconnection of the electrical path from a deadfront apparatus to the feeder cables connected to the apparatus bushings without moving the feeder cables and while providing visible-break isolation. Connector systems are known including a removable link or positionable connector assembly extending between a deadfront junction mounted to the electrical apparatus proximate the bushing of the apparatus and a mating connector joined to a cable. When the linking assembly is removed and the connector assembly is repositioned, the visible link is immediately recognizable. While such connector systems for deadfront apparatus can be effective to provide the visible break, they can be complicated to use, and generally require that the cables be de-energized prior to operation of the connectors. It would be desirable to provide a deadfront visible break that can be operated while the cables are energized, especially for medium voltage switchgear apparatus and the like.
Additionally, known separable loadbreak connectors are operable in “loadmake”, “loadbreak”, and “fault closure” conditions. Considerable arcing can occur in any of the operating conditions when energized connectors are joined and separated. It would be desirable to reduce arcing intensity as the connectors are mated and separated.